nl80211: increase the max number of rules in regdomain

Some network cards (Intel) produce per-channel regdomains and rely on
cfg80211 to merge rules as needed. This hits the max rules limit and
fails.

Signed-off-by: Arik Nemtsov <arikx.nemtsov@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>